Sewing machine



Aug. l1, 1942. R. A. coLLlNs 2,292,432

SEWING- MACHINE Filed June 28, 1939 2 Sheets-'Sheet 1 /25 @QP Wam' Aug. l1, 1942. R. A. coLLlNs SEWING MACHINE Filed June ze, 1939 2 sheets-sheet 2 INvN-m Patented Aug. ll, 1942 SEWING MACHINE Ralph A. Collins,

White Plains, N. Y., Aassignor to The Reece Button Hole Machineompany, a corporation of Maine Application June 28, 1939, ASerial No. 281,548

.(Cl. i12-74) Claims.

This invention relates to sewing machines of the type designed to sew a suitably positioned line of stitches around an area or opening such as a button hole, in the work, and more particularly to the work-clamping mechanism employed in such machines.

In button hole and similar sewing machines, the work-clamping mechanism usually comprises two clamps on the bed frame of the machine which are movable to and from each other and normally yieldingly urged toward each other. Each of these clamps consists of a work-supporting plate and a therewith cooperating clamping foot between which and the plate the work is clamped. After clamping the work, it is customary to spread the clamps, i. e., to move the plates with their respective clamping feet slightly away from each other in order to stretch or tension the work or to spread a button hole or other slit therein, as the case may be. Usually, the clamps are spread automatically into a predetermined maximum separated position after the machine has been started and before the actual sewing begins. It is also customary to provide stops for the work clamps, hereafter called inner-limit stops, to limit the approach of said work clamps toward each other. These inner limit stops are usually adjustable to and from each other in the direction of the movement of the clamps so that the latter, when moved from said stops outwardly into their maximum separated position, will traverse a distance which is just suflicient to effect any desired tension in, or spread of, any type of clamped material.

To spread the clamps into their maximum separated position, it is customary in machines of the type under consideration to employ a cam or spreader block which is mounted on a frame that carries the stitching instrumentalities, hereafter called the stitch frame. Usually, the stitch frame also carries, without the operating region of the stitching instrumentalities, means for cutting la button hole or other slit in the stitching area of the clamped work. In order that .both the cutting operation and the stitching operation may be performed during one uninterrupted operating cycle of the machine and while the work remains clamped, the stitch frame and the bed frame have relative movements in order to bring Vthe stitching area of the clamped work on the bed frame from operative alignment with the cutting means, i. e., the cutting position, into operative alignment with the stitching instrumentalities, i. e., the stitching position, and vice versa. As it is during the `first of these relative movements vin each operating cycle of the machinev that the spreader block onthe stitch frame engages suitable followers of the work clamps and performs its clamp-spreading function, and inasmuch as the work has to be already tensioned or spreadat the beginning of the stitching operation, said-first relative movement between the frames 'takes place from the cutting position into the stitching position. VIn additionto the before mentioned relative movements -from cutting to stitching position, and vice versa, the stitch at the end of the first relative movement in each working cycle between said frames from the cutting into the stitching position.

The present invention has for v`its primaryV object to provide novel means for holding the work clamps in their maximum separatedk position, against their normaltendency to ryield toward each other, immediately after the spreader kblock has forced the work clamps into their maximum separated position and cleared the followers thereof and during the remaining operating cycle of the machine, and without interfering in the least `with the requisite relativemovements loetween the stitch frame and the bed frame during said remaining operating cycle.

Before explaining in ydetailthe presentinvention it is to be understood that the invention is Vnot limited in its application to thedetails of construction and arrangement of parts illustrated in the accompanying drawings, ysince the Iinvention is capable of other embodiments and of being practiced or carried Vout in vVarious ways. Also it is to be understood that the phraseology or terminology employed hereinis forthe purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of .the prior art.

In the drawings:

Fig. 1 is a fragmentary side elevation, lpartly in section, of a sewing machine, includingia work-clamping mechanism which embodies the present invention.

Fig. 2 is a fragmentary plan View of the machine with the stitch frame thereof vpartly-broken away for better illustration of the work-clamping mechanism underneath.

Fig. 3 is an enlarged section, taken substantially on the line 3 3 of Fig. 1 and showing the work-clamping mechanism in perspective.

Fig. 4 is an enlarged, fragmentary perspective view, partly in section, of certain cooperating elements of the work-clamping mechanism.

Fig. 5 is a longitudinal section through a modifled construction of the work-clamping mechamsm.

Fig. 6 is a fragmentary section, taken substantially on the line 6 6 of Fig. 5.

Referring to the drawings and particularly to Fig. 1 thereof, the present invention is shown as applied to a button hole sewing machine of a well-known type, comprising a stationary bed frame I5 which carries the work-clamping mechanism hereinafter described, a movable stitch frame or head I6 with the stitching mechanism, and mechanism on the stitch frame for cutting a button hole or the like. The stitch frame I6 is movable longitudinally over the bed frame I5 to bring the stitching and cutting mechanisms alternately into operative relationship with the work, and is also movable both longitudinally and laterally to position the stitches in accordance with the work to be performed, by means of feeding mechanism operated by a main cam I1 which is carried by the stitch frame I6 and rotated by any suitable power driven shaft (not shown) This feeding mechanism is well known in the art, being shown, for example, in the Patents to Reece No. 240,546, April 26, 1881, and No. 655,637,

August ,7, 1900, and many others, and requires no detail description herein.

The stitching mechanism comprises a needle I9 carried by a needle bar 26, and looper mechanism I4 which may be substantially as shown in the patent to Grip No. 1,905,854, April 25, 1933, said needle bar and said looper mechanism being carried by upper and lower turrets 2I and 22, respectively, which are rotated in unison at the proper time by gear segments (one being shown at 23 in Fig. 1) that are carried by a rock shaft 25, operated by the main cam I 1 in a manner further described in the Reece patents above referred to. The lower turret 22 also carries a throat plate 26 through which the needle I9 passes in .order to cooperate with the looper mechanism I4,

The needle bar 29 is reciprocated vertically and vibrated laterally in its turret 2I in a manner substantially as shown and described in the patent to Reece No. 1,991,627, February 19, 1935. The looper mechanism I4 is operated in a manner substantially as shown and described in the patent to Grip above referred to and in the patent to Dunnell No. 1,935,083, November 14, 1933.

The cutting mechanism comprises upper and lower cooperating cutting elements 30 and 3I, respectively, the former being carried by a lever or arm 32 which is operated at the proper time from the main cam I1 in a manner described more fully in the patent to Kiewicz No. 1,841,133, January 12, 1932.

It will be understood that in machines of this character suitable mechanism is provided whereby the machine, when started, will perform its operative cycle and then stop automatically, said cycle including, rst, the clamping of the work by the work-clamping mechanism, then a movement of the stitch frame from the cutting position shown in Fig. 1, in which the cutting elements 30, 3l are adjacent the stitching region or area of the work, into the stitching position in which the stitch-forming instrumentalities are adjacent said area, next, a stitching operation of the character determined by the design of the feed mechanism, then a return of the stitch frame into the cutting position, and finally the release of the work from the work-clamping mechanism, said cycle also including a cutting operation which may be performed either before or after the stitching operation according to the design cr adjustment of the machine.

Except as hereinafter pointed out, or as they enter into combination with the parts hereinafter described, the mechanisms above referred to specifically form no part of the present invention and may be as shown and described in the patents referred to, or otherwise, as will be well understood by those skilled in the art.

The'work-clamping mechanism in the present machine is in most respects like the one shown and described in the copending application of Walter E. Nichols, Serial No. 272,780, led May 10, 1939, which has resulted in Patent No. 2,201,449. Accordingly the Work-clamping mechanism consists of two relatively movable clamps 35 and 36, each comprising a Work-receiving clamp plate 31 and a therewith cooperating clamping foot 38 which is carried by a slightly resilient arm 39, pivotally mounted at 40 on a block 4I which is adjustably mounted on the plate 31 in the manner shown in Figs. 1 and 2. The clamp plates 31 are slidably supported on the upper machined surface 42 of the bed frame I5. Bordering the opposite sides of the machined bed surface 42 are raised ledges 43. Each clamp plate 31 carries a matrix 44, having its work-engaging surface 45 knurled or otherwise roughened the same as the sole of the therewith cooperating clamping foot 38, so that the clamped material therebetween maybe more firmly gripped.

The clamp plates 31 are guided for linear movement at right angles to the longitudinal axis .7J- (Fig. 2) of the line of stitching which is determined by the design of the feed mechanism. This is accomplished by providing linkages 41 between the clamp plates 31 and the bed frame I5 in a manner fully described in the above co-pending application. As these linkage are identical in every respect, the following brief description of one linkage is deemed sufficient for an understanding of the operation of both linkages. Each linkage 41 consists of two levers or links 4B and 49 which are pivotally mounted at 50 and 5I, respectively, on the underside of the bed frame I5 and floatingly pivotally connected with each other at 52. lIhe front link 49 has a floating pivotal connection 53 with a slide 54 which is guided on the underside of the bed frame for movement at right angles to the longitudinal stitching axis .1J- (Fig. 2) and longitudinally adjustably connected at 55 with its respective clamp plate 31 near the front end thereof in a manner further described in the above-mentioned copending application. The rear link 48 has a floating pivotal connection 56 with said clamp plate near the rear end thereof, said connection being afforded by a pin 56a on said rear link 48 and a longitudinal slot 5617 in the Linderside of the clamp plate into which said pin projects. Movement of the slide 54 in either direction causes movement of the clamp plate 31 in either direction at right angles to the longitudinal stitching axis .7c-cc, whereby said clamp plate is solely guided by its linkage 41, as will be readily understood.

Adapted to cooperate with the opposite. in-

clined ends 51 of the slides .54 ofthe linkagesl41 are the inner-limit stop surfaces 58 of a nonrotatable wedge member 59, carried by a screw 60 which is rotatably but axially immovably -mounted in the depending skirt "6I of the bed frame I5, all as described more fully in the abovementioned co-pending application. Manual rotation of the screw 60 causes movement of the wedge member 59 in the direction of thestitching axis :t-x (Fig.2) and, hence, adjustment of the inner-limit stop surfaces Y58 relative to the slides 5. A tension spring 62suitably anchored to the slides 54, normally urges said slides into engagement with the wedge member 53 and the clamp plates 31 toward each other, the:latter through intermediation Vof the linkages i1 as will be readily understood. Mounted on the raised ledges 43 of the bed frame I5 by Ymeans of screws 63 are two latch plates64 for holding the clamp plates 31 down on their supporting surface 42.

Suitably mounted at B5 on the stitchframe I6 is a spreader block or cam 36 (Figs. 1 and 2) which is adapted to engage followers 51 on the underside of the clamp plates V31 and force the latter away from each other into a maximum separated position against the rtendency of the spring-urged linkages l1 to force said clamp plates toward each other. This is accomplished after the material or work W has been clamped and while the stitch frame I3, and with it the spreader block B6, is moved by the feed mechanism from the cutting position shown in Figs. 1 and 2 into the stitching position, i. e., ,to the left as viewed in Figs. 1 and v2. The. result is a tensioning or spreading of the clamped material to an extent which is determined by the adjustment of the wedge member 59, as will be readily understood. For previously stated reasons, the spreader block is so .constructed and arranged on the stitch frame I6 that it will have completely cleared the followers'l of the clamp plates 31 when the stitch frame arrives in the stitching position. To prevent, however, that the spring-urged linkages 41 yield the spread clamp plates 31 toward each other after the spreader block 66 has cleared the followersof said clamp plates, means hereinafter described hold the clamp plates in their maximum separated ,position until the end of the .operating cycle.

After the machine has been started for an operating cycle and before the stitch frame I6 is moved from the cutting position to the stitching position, i. e., before the work clamps are spread into their maximum separated position by the spreader block 6B, the clamping feet 38 are auto- Amatically lowered and pressed against the work W on the clamp plates 31 by mechanism which is shown and described in detail in the `patent to Kiewicz, No. 1,841,133, January 12, 1932. To this end, the rocker 863, which is pivotally mounted at 8| on the underside of the bed frame I5, has two spaced arms 82 (Figs. 1 and 2), each terminating in a roller-shaped end `83 which is received in the forked end 84 of an extension 85 of a clamp arm 3S. The rocker 80 carries `a depending bracket 83 which pivotally supports at 81 one end of a toggle member 88, the other end thereof being pivotally connected at 89 vwith one end of a cooperating toggle member 9U. The other end of the toggle member 90 is pivotally Vmounted at 9i on the bed frame I5 and has an extension 92 formed as a handle for manualoperation of lthe toggle members 88 and 90, if 4desired. A tension spring93, anchored .with-one tion, the rclamping feet 38 are in the illustrated raised, dotted line position. For the purpose of automatically lowering the clamping` feet 38 into firm engagement with the work W on the clamp plates 31, the lower toggle member 88 is provided with a laterally extending arm with which a lever 96 is adapted to cooperate. This lever 96, which is suitably pivoted on the bed frame I5 and shown vin dotted lines in its home position (Fig. l), is provided with a follower 91 which is normally urged `into cooperative-engagement with the main cam I1 of the machine by a suitably anchored tension spring 98, The main cam I1 is provided with a cam lobe 39 which is adapted to depress lever 93 from the dotted line position into the full line position shown in Fig. 1 shortly after the machine has been started. While the lever 96 is thus being depressed, the same engages and rocks arm 95 into the full line position shown in Fig. 1, with the result that the toggle members 88 and 9|] are rocked intol their full line postion (Fig. l) 4and the clamping feet 33 are lowered into their full line position (Fig. 1) in which they are in clamping engagement with the work W. The lever 96 disengages from the arm S5 and is yielded into its dotted line position (Fig. Vl) immediately after the crest 39a of the cam lobe 3Q clears the follower 91. Provisions are also made to prevent the free collapse of the toggle me-mbers 88, 9B in their full line position (Fig. l) To this end, the toggle members 38, 3E are provided with shoulders lil@ and Il, respectively, which engage each other when said toggle members lassume the full line position in Fig. 1 in which their pivot connection 39 is slightly to the left of a straight line passing through their other pivot connections 81 and 3l with the Ybracket 36 and the bed frame I5, respectively. Thus, the shoulders IDG and lili, in conjunction with the spring 33, effectively prevent the Vcollapse of the toggle Amembers 88, 32B in either direction, and permit their collapse into the dotted line position in Fig. 1 only after the toggle members have been rocked against the tension of the spring 9?. from the full line position into a position in which their pivot connection 83 has moved to the right as viewed in Fig. 1 beyond alignment with a straight line passing through theirl other pivot connections -81 and 9i with the bracket 86 and the bed frame I5, respectively. The toggle members 38, 93 are automtically collapsed at the end machine from the cutting to the stitching .position. To this end, the roller-shapedends 83 vof the rocker 33, aswell as the forkedrends 84 of the clamp arms 39 are inclined to the planeof the vclamp plates 31 in the manner shown vin Figs. 3l and- 4. After the .arms `3Sl..with .their clamping feet 33 have been rocked into clamping engagement with the work W on the clamp plates 31 in their inner-limit position (Fig. 3), the latter are forced into their maximum separated position by the spreader block 66, whereby the forked ends 8d of the clamp arms 39 slide outwardly on the roller-shaped ends 83 of the rocker 80, as will be readily understood. When the spreader block 66 clears the followers El of the clamp plates 31, the forked clamp arm ends 8a become inmediately wedged against the roller-shaped rocker ends 83 with such force that said clamp and, hence, the clamps are rmly held in their maximum separated position in spite of any vibration of the machine and despite the tendency of the spring-urged linkages il to return the clamps to their inner-limit position. This appears clearly from Fig. 4 wherein the indicated pull-down force F exerted by the rocker 8l! keeps the opposite, inclined surfaces H8 and HI of a roller-shaped rocker end 83 and a forked clamp arm end 8f3, respectively, in firm engagement with each other, thereby preventing the yielding of said clamp arm and its respective clamp plate from the maximum separated position shown in full lines into the inner-limit position shown in dotted lines. The inclination of the roller-shaped rocker ends 33 and of the therewith cooperating clamp arm forks i513, the resiliency of the clamp arms 39 and the pull---down force F of the rocker 86 are, of course, so. related that the work W remains firmly clamped on the plates 3? even after said clamp arm forks 84 have been moved on and relative to their respective roller-shaped, inclined rocker ends 83 outwardly inte the maximum separated position. The clamp arms Sil and their respective clamp plates 3l are evidently held in the maximum separated position by the rollershaped rocker ends 83 and the therewith cooperating clamp arm forks 84 until the work is automatically released from the clamps at the end of an operating cycle of the machine, whereupon the spring-urged linkages il will return the clamp plates 37 to their inner-limit position.

Figs. 5 and 6 disclose a modied work-clamping mechanism wherein the clamp arms 39 are rotatably and axially slidably mounted on pivots H5 which are slightly inclined to the plane of the clamp plates 3l and lie in a plane which extends at right angles to said plane of the clamp plates and parallel to the direction of movement of the latter. Each pivot H5 is carried by the spaced arms H6 of a block H"| which is mounted on the bed frame l5, while the hub H8 of each clamp arm 39 is straddled by the spaced forked arms H9 of a bracket |20 which is mounted on a clamp plate 31 so that said clamp arm is axially movable with its clamp plate 3l relative to its pivot H5. To provide for uniform engagement of the end surfaces |22 of each clamp arm hub H8 with the surfaces |23 of the straddling arms H9 of a bracket |20 in any angular position of the clamp arm, the surfaces |22 and |23 lie in planes which are parallel to the rocking plane R-R (Fig. 6) of said clamp arm. The fork legs 85a of the clamp arms 39 may be disposed as shown in Figs. 5 and 6 and the fork-engaging ends 83a of the rocker 86 may be of the shape shown in section in Fig. 6 or any other suitable cross-sectional shape. It is evident that, when the rocker ends 83a maintain the clamp arms in clamping engagement with the work, said rocker ends and the inclined pivots H5 cooperate to Wedge said clamp arms against yielding from their maximum separated position into their inner-limit position in the -direction of arrow |25 (Fig. 6)

It is also conceivable to mount the clamp arms 39 axially immovably on their pivots l5 (Fig. 6) and to axially slidably support the ends of said pivots H5 in the spaced arms H6 of the blocks H1.

I claim:

1. In a sewing machine, the combination of a work-supporting surface; a pivot; a thereon pivoted, axially movable member rockable into and out of clamping engagement with the supported work; and an element engaging said member and operable to force the latter in any axial position into clamping engagement with the supported work, at least one of the engaged surfaces of said member and element being inclined to the pivot axis whereby said member is wedged against axial movement in one direction While said element maintains the member in clamping engagement with the Work.

2. The combination in a sewing machine as set forth in claim 1, wherein said element is so movable and coordinated with said member as to rock the latter in any axial position into clamping engagement with the work.

3. The combination in a sewing machine as set forth in claim 1, wherein said element is so movable and coordinated with said member as to rock the latter in any axial position out of clamping engagement with the work.

4. The combination in a sewing machine as set forth in claim l, wherein said element is so movable and coordinated with said member as to rock the latter in any axial position into and out of clamping engagement with the Work.

5. In a sewing machine, the combination of a work-supporting surface; a pivot element; a thereon pivoted, axially movable clamp having a fork; and a member movable in a plane at right angles to said surface and having a finger element traversing said fork in any axial clamp position for rocking said clamp into and out of clamping engagement with the supported work, said elements being so inclined to each other that the clamp is wedged against axial movement in one direction while said finger element maintains said clamp in clamping engagement with the Work.

6. The combination in a sewing machine as set forth in claim 5, wherein said pivot element is parallel to said surface and said finger element is inclined to said pivot element.

7. The combination in a sewing machine as set forth in claim 5, wherein said pivot element is axially immovable and inclined to said surface and said finger element is axially parallel to said surface.

8. In a sewing machine, the combination of a work-supporting surface; a clamp member closable against the supported work and movable in a predetermined path parallel to said surface; and a member immovable in the direction of said path and operable to engage said clamp member in any position on said path and maintain it in clamping engagement with the supported work at least one of the engaged surfaces of said members being so inclined to said supporting surface that said clamp member is wedged against movement in one direction of said path While clamping the work.

9. In a sewing machine, the combination of a work-supporting surface; a pivotally mounted clamp bodily movable in opposite directions in a plane parallel to said surface; and an element immovable in said opposite directions and engaging said clamp and operable to force said clamp in any bodily position into clamping engagement with the supported work, at least one of the engaged surfaces of said clamp and element being so inclined to said supporting surface that said clamp is wedged against bodily movement in one of said opposite directions while said element maintains the clamp in clamping engagement with the work.

10. In a sewing machine, the combination of a work-supporting surface; an axially movable clamp pivotally mounted about an axis parallel to said surface; and an element engaging the clamp and being movable in a plane substantially parallel to the rocking plane of said clamp for rocking the latter in any axial position into and maintaining it in clamping engagement with the supported work at least one of the engaged surfaces of said element and clamp being so inclined to said supporting surface that said clamp is wedged in any axial position against axial movement in one direction while said element maintains said clamp in clamping engagement with the work.

1l. The combination in a sewing machine as set forth in claim 10, wherein said element has a nger, said clamp has a fork of which the spaced legs extend longitudinally at right angles to the pivot axis of the clamp and lie in parallel planes inclined to said pivot axis, and said legs are so wide as to receive said finger in any axial clamp position.

12. In a sewing machine, the combination of a work clamp including a work plate movable in opposite directions in the plane of said plate, and a member pivoted on said plate; and an element engaging said member and being movable in a direction other than said opposite directions for rocking said member into and maintaining it in any plate position in clamping engagement with the work on said plate, at least one of the engaged surfaces of said member and element being so inclined to said plate that the latter is wedged against movement in one of said opposite directions while said member is in clamping engagement with the work.

13. In a sewing machine, the combination of a work supporting surface; two pivotally mounted clamps bodily movable to and from each other in a plane substantially parallel to said surface; and an element engaging said clamps and adapted to `simultaneously rock said clamps in any bodily position into and maintain them in clamping engagement with the supported work at least one of the engaged surfaces of each clamp and said element being so inclined to said supporting surface that each clamp is wedged in any bodily position against movement in one of the opposite directions of its to and fro movement while said element maintains the clamps in clamping engagement with the work.

14. In a sewing machine, the combination of a work clamp including two work plates movable parallel to their surfaces to and from each other, and two members pivoted on said plates; and an element engaging said members and adapted to simultaneously rock the latter into and maintain them in any position of their plates in clamping engagement with the Work on said plates at least one of the engaged surfaces of each member and said element being so inclined to said plates that each plate is wedged against movement in one of the opposite directions of its to and fro movement while said element maintains the members in clamping engagement with the work 15. In a sewing machine, the combination of a plane support; two plates movable with their surfaces on said support to and from each other and normally yieldingly urged toward each other; two clamps pivoted on said plates and movable therewith; and a member engaging said clamps and adapted to simultaneously rock said clamps into and maintain them in clamping engagement With work on said plates at least one of the engaged surfaces of each clamp and said member being so inclined to said plates that each plate is wedged against yielding toward the other while said member maintains the clamps in clamping engagement with the Work.

RALPH A. COLLINS. 

